Managing New Orleans Flood Risk in an Uncertain Future Using Non-Structural Risk Mitigation

This dissertation addresses one of New Orleans' most critical challenges: how to make the city more resilient and less vulnerable to future flood damages. The author considers proposals to augment the existing protection system with “nonstructural” risk mitigation programs focused on single-family homes, including incentives for elevating existing or new structures, revised building codes, incentives for relocation to lower-risk areas, and land use restrictions designed to curtail future growth in the floodplain. He develops a low-resolution scenario generator designed to produce first-order estimates of property risk from 2011 to 2060 across a range of uncertain future scenarios, and applies exploratory modeling and robust decisionmaking methods to (a) suggest strategies that balance risk reduction and implementation costs across many or most plausible futures, and (b) identify scenarios in which current alternatives yield negative net economic benefits or excessive levels of residual risk. Nonstructural risk mitigation strategies appear to provide cost-effective risk reduction in high-risk neighborhoods and help to hedge against futures in which damages from more-frequent annual events are greater than expected. However, substantial residual risk remains from lower-frequency events, even with large investments in nonstructural risk mitigation.